add first test

Signed-off-by: andrusenkoau <andrusenkoau@gmail.com>

nemo/collections/asr/parts/context_biasing/context_graph_ctc.py

@@ -67,7 +67,7 @@ class ContextGraphCTC:
     A ContextGraph contains some words / phrases that we expect to boost their recognition accuracy.
     """
 
-    def __init__(self, blank_id=1024):
+    def __init__(self, blank_id: int = 1024):
         """
         Initialize the ContextGraphCTC based on given blank_id.
 
@@ -79,7 +79,7 @@ def __init__(self, blank_id=1024):
         self.root = ContextState(index=self.num_nodes, is_end=False)
         self.blank_token = blank_id
 
-    def build(self, word_items: List[Union[str, List[List[int]]]]):
+    def build(self, word_items: List[Union[str, List[List[Union[str, int]]]]]):
         """
         Build the context graph based on given word_items.
 

tests/collections/asr/test_asr_context_biasing.py

@@ -0,0 +1,29 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import os
+from functools import lru_cache
+import pytest
+import torch
+from nemo.collections.asr.parts.context_biasing.context_graph_ctc import ContextGraphCTC
+
+
+class TestContextGraphCTC:
+    @pytest.mark.unit
+    def test_graph_building(self):
+        context_biasing_list = [["gpu", [['▁g', 'p', 'u'], ['▁g', '▁p', '▁u']]]]
+        context_graph = ContextGraphCTC(blank_id=1024)
+        context_graph.build(context_biasing_list)
+        assert context_graph.num_nodes == 8